Recent Work on the Influence of Cell Size

THE BEE LABORATORY
Science is nothing but trained and organised common sense.-Huxley

RECENT WORK ON THE INFLUENCE OF CELL SIZE.

H. Gontarski has studied the influence of cell size on the phaenotypic variation of the honey bee (Zts. f. Morph. u. Oekol. d. Tiere; Abt. A. Zts. f. wiss Biologie, Bd. 29, H. 3, 1935). He finds that the greatest percentage increase in size takes place if cells of 5.74 mm. diameter are used; that is, foundation with 700 cells per sq. dm. He points out that the variation in size of individual bees in a colony is partly due to phaenotypic variation due to the cell size, and partly to differences called forth by the quality and quantity of food – differences, in fact, that are similar to, but less than, those which cause a worker larva to become a queen when suitably fed and nursed. His big bees had the normal worker number of ovarian tubules – maximum 20 – so did not show any hyper-trophy of the ovaries nor had they developed spermathecae. They were in other anatomical respects also normal workers. There is thus little fear that such bees would be more queenlike in their instincts, and perhaps not such keen foragers as smaller bees.

The author thinks that the influence of the cell is mainly exerted indirectly, by providing more room for food; but does not deny a possible direct influence as well, due to more room for growth.

In another paper (Zts. f. vergl. Physiol. Bd. 21, H.5. 1935) he deals with cell dimensions, and shows that they depend partly on the size of the bees and partly on the condition of the colony at the moment and its inclination or disinclination to build.

Bees appear to perceive the size of the cells in foundation with the aid of their legs. They probably “realise” the cell as a whole, and there are limits to the size of cell-base to which this realisation can extend; so that foundation with bases larger than drone comb is drawn out quite irregularly. Bees probably have an instinctive tendency to continue unfinished work as it was begun-this is important for ensuring the carrying out of the work of the hive in a steady and regular manner.

There is a certain size of cell-base at which the bees tend to switch over from worker to drone cells. This appears to be larger the more the strain of bees tends to non-swarming propensities.

The queen is evidently able to recognise the size of cells, for she delays laying when given comb with cells of abnormal sizes. Two stocks were given empty frames in April, in which they built drone comb. The cells were noted to be very irregular in size; the queens laid in the smallest cells first (and the largest last), suggesting that they only reach the “mood” for laying unfertilised eggs gradually, as the season advances.

The impulse to lay “drone” eggs seems to depend, not on the absolute size of the cells, but on a perception of the difference between the two sizes of cell, which acts as a kinaesthetic stimulus to the queen’s nervous system and thus to her spermatheca.

Large cells have been a frequent subject of discussion in many bee journals of late. R. Graftiau (L’ Apiculteur, February) mentions that one can get combs of large cell foundation beautifully drawn out if one gives them to weak stocks on 4 or 5 combs only, is well as in swarms, natural or artificial. S. Sevin (the same, January) compares the surplus and winter stores of stocks on various cell sizes, to the advantage of large cells.

The last-named author also discusses (February) the number of cells per sq. dm. and a formula for deducing them from the width of a cell. He makes the error – with which everybody should now be familiar, since it is annually exposed when made in connection with the timing of motor races and other fast sporting events- of carrying his calculations to more significant figures than the attainable accuracy warrants. (Incidentally, Armbruster published a note on this formula in 1932; Arch. f. Bienenk, XIII 7/8) ). The formula as usually given is inconvenient to use, as it must be worked out on paper at some length. The following may therefore be of use to those buying foundation and desiring to know its size.

N is therefore roughly equal to the square of 1-1/2 times the number of cells in a dm. length, or to the square of the number in 15 cm.

When we proceed to inches, the rule is equally easy, since N is the square of the number of cells in 1.52 X 3.94 inches, or nearly 6 inches. Thus, if there are 26 cells in 6 inches, N is 26 X 26, or 676 cells per sq. dm.

The rule is therefore: – Count the cells in 15 cm., or in 6 ins., and square this number.

To obtain the number per sq. inch, count the cells in 1-1/2 inches and square. This figure is approximately 15.5 times less than that for a sq. dm., since a sq. dm. = 15.5 sq. inches.